Voxel approach for 3D in-plane homogenized failure surfaces of non-periodic masonry

While many historical masonry structures consist of brick masonry where the units display a periodic arrangement (such as stretcher or running bond), there are several examples that instead consist of stone masonry. Here, the blocks present different shapes and dimensions, and are assembled with random arrangements - hence the name "non-periodic masonry". This work presents a Matlab script for the extraction of in-plane homogenized failure surfaces for this type of masonry, and they represent a macroscopic strength criterion for the considered masonry panel. The failure surfaces are obtained through the solution of an upper bound limit analysis problem, formulated as a standard linear programming problem. The 3D finite element mesh used for representing the considered panel is created according to a voxel approach: starting from the rasterized image of the masonry panel, each 2D pixel is extruded to become a 3D voxel, which is subsequently transformed into a finite element. For numerical validation, the in-plane homogenized failure surface is extracted for a sample masonry panel, along with the failure modes for several load conditions, and they are critically commented.